asp.net webform can't find usercontrol - asp.net

Question

I don't know how to get usercontrol's function GetValue(), I always get Error code CS1061.
First I can't get usercontrol ID testControl.
I have found lots example, but almost example can use like my code.
I don't know what's wrong about it.
This is all my code.
User Control Part
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="testControl.ascx.cs" Inherits="MyWeb.UserControl.testControl" %>
<%# Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %>
<style type="text/css">
.center {
text-align: center;
}
</style>
<asp:UpdatePanel ID="upUserControl" runat="server">
<ContentTemplate>
<table>
<thead>
<tr>
<td colspan="4">
<div class="center">
<asp:Label ID="lblTitle" runat="server" Text="查詢"></asp:Label>
</div>
</td>
</tr>
</thead>
<tbody>
<tr>
<td><asp:Label ID="lblName" runat="server" Text="姓名"></asp:Label></td>
<td><asp:TextBox ID="txtName" MaxLength="10" runat="server"></asp:TextBox></td>
<td><asp:Label ID="lblIdentify" runat="server" Text="身分證字號/統編:"></asp:Label></td>
<td><asp:TextBox ID="txtIdentify" MaxLength="10" runat="server"></asp:TextBox></td>
<td><asp:Button ID="btnQuery" runat="server" Text="查詢" OnClick="btnQuery_Click"/></td>
</tr>
</tbody>
</table>
</ContentTemplate>
</asp:UpdatePanel>
Code Behind of User Control
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace MyWeb.UserControl
{
public partial class testControl : System.Web.UI.UserControl
{
public string Name, Identify;
public string GetValue()
{
return txtName.Text + txtIdentify.Text;
}
protected void Page_Load(object sender, EventArgs e)
{ }
protected void btnQuery_Click(object sender, EventArgs e)
{ }
}
}
asp Page
<%# Page Title="Home Page" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="testDynamicSelect.aspx.cs" Inherits="MyWeb.testDynamicSelect" %>
<%# Register Src="~/UserControl/testControl.ascx" TagPrefix="ucTest" TagName="ctrl" %>
<asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server">
<ucTest:ctrl runat="server" ID="testControl" />
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" />
</asp:Content>
Code Behind of asp Page
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace MyWeb
{
public partial class testDynamicSelect : Page
{
protected void Page_Load(object sender, EventArgs e)
{ }
protected void Button1_Click(object sender, EventArgs e)
{
//I can't get testControl
Response.Write(testControl.GetValue());
}
}
}

Answer 1

I try to reference namespace MyWeb.UserControl, and it can work now.
In my company old project, it wouldn't reference just like my question.
But in my new project can't work. It have to reference namespace MyWeb.UserControl.
Who can tell me how it work?
using MyWeb.UserControl;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace MyWeb
{
public partial class testDynamicSelect : Page
{
testControl ucl = new testControl();
//UserControl ucl = new UserControl;
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
Console.WriteLine(cul.GetValue());
//Button1
}
}
}